Top surface of concrete and the like and method of forming the same



' May 1932- N. c. JOHNSON TOP SURFACE OF C ONCRETE AND THE LIKE AND METHOD OF FORMING THE SAME Filed Aug. 24, 1928 avwcwotoz' Mam fi/msa/v Patented May 10, 1,932

TBS

NATHAN c. :ron nsoim or nnennwoongnnw JE SEY TOP sunriicn or concerns. nn THE LIKEY'QND mention on rem/ ime Application filed. august 24, 1 928. s x-1a sci-e82, i

This invention relates to top surfaces of concrete and the like, and to methods of forming such surfaces, for example roadways, floor slabs, plaza areas, sidewalks,'and other traflic 5 carrying surfaces.

. which Will be pleasing inappearance and The objects of this invention include the provision of durable, inexpensive surfaces or pavements of the above indicated character,

Io from which various dangerous or undesirable characteristics of the usual forms of pavements areelnnlnated. v i

Further and more-specific objects, features and advantageswill clearly appear from the ments of the invention.-

jtio-nf'or treating" concrete, issued'July 26 detailed description given below,taken in connection with the accompanying drawings which form part of this specification and illustrate by Way of example certain embodi- -The invention'consists in the novel methods and steps of processes set forth by Way of example in the following specification, together with the resulting product or products and the novel features thereof. i i 1 Inthe drawings, Fig. 1 is'across-sectional view illustrating one embodiment of my invention as applied to pavement orsid'ewalk construction; and I Y Figs. 2' and 3 are views similar to Fig. 1, but

H showing alternative embodiments of my invention;

According to the embodiment illustrated in Fig.1, the main body of? concrete as at 10, of a pavement or other construction may be poured in any suitable Well-known. manner, but, before the surface at 11 is allowed to harden, a suitable material for inhibiting or delaying the settingaction f is brushed I or sprayed upon the surface. Suita-blefmedication. 2 substances adapted. to thispurpose are described in my'copcnding application Ser;

Process of and materials for treating concrete, of Whiclrthis application is inv the nature of a'continuation. Suchmaterials are al'so'morefully set forth in my Patent'No. 1,637,321, entitled Method of and composi- 1 927, of which said copending application is in part-a continuation.

aggregate "particles, from'thefupper poi-'- l i I tionsof hich the cement. has been removed. 7 No. 99,330, filed August 2,, l926, 'entitled 5 According to processes: disclosed in 1 said patent and said application, the concrete surface is treated With 'a suitable medication todelay or prevent the setting ofthecement at thesurface layers, so that after the main body ofthe concrete is hardened, such surface layers of cement may be brushed' or washed away, leaving the stone or other aggregate particles exposed to the desireddegre'e'. The I f medication substance may be applied as ex: plained in mysaid patent, so'as toafi'ectthe concrete only to a predetermined depth, deipending upon the extent to which it is desired,

to reveal the aggregate forvariou-sconditions 'o'fuse.-" E a:

As explained: in said patent; the case of Wall surfaces the material embodying the medicationdmay' be conveniently applied to I the forms into which the concrete is poured 7' and the concrete in fibwing against the forms, 6

"Will come: into proper contact with the treat ing material toinsure uniform" treatment.

However; in the case of top surfaces=,' in{ order to insure uniform treatment of all parts 'of the concrete and" after the same is suitably eed-led and; either before orfafter'theinitial setting action takes 3 place, the medication substance is sprayed' or Y uniform-1y brushed 8 over the" concrete surface. "When the medication? is carried in a suitable colloidal or drying vehicle, a soft "film thereoffwill be formed on the concrete and afterjthe main f body ofthe concrete has becom'e hardened, the remainingin-gredie'nts of this film may be face as indicated at 11',Which will berelati ve-f 1 y rough and irregular due to theprotruding The pavement or other tra-flic vvayformed H the surface, I 'find-i-t preferable to firstpour 85 readily removed as by the use ofwire} brushes and by washing. This will'leavea top surin the'above described manner to remove the surface layers of cement and to reveal the aggregate. The roughened surface 11 with the numerous protruding aggregate particles provides a very eflicient bonding surface, so that when the layer 12 is applied thereto, an actual monolithic construction is obtained.

Either of the surfaces 11 or 13 prepared in the abovedescribed manner will provide an efficient non-slip and non-skid pavement and offer an exceptional security of traction and freedom from skidding when the construction isused for highways. Such surfaces also provide an eflicient friction grip which, especially on grades, will lessen the wear on tires inasmuch as abrasion and wearing of the'tires due to slipping is substantially eliminated. On rainy nights, when the usual smooth surface type of pavements reflect a most troublesome and dangerous .glaring light in the eyes of vehicle drivers, with surfacepave-ments as above described, there is a uniform diffusion of the beams from the headlights substantially without glare. Strong sunlight is likewise diffused, which makes for comfort and safety of the drivers. Pedestrian travel, both on sidewalks and at road crossings, is also made more safe as aresu'lt of the non-slip qualities of surfaces treated according to my invention. The invention may be applied also to stairs, steps, tennis courts, or-other places where there is danger of slipping especially in wet Weather.

Withthese various uses, the depth to which the aggregate is revealed may be varied and determined by using the medication substance in proper quantities and concentrations, which may be best determined by trial according to the data set forth in my above mentioned patent.

In some instances it may be found convenient or desirable to use acids or other reagents for removing the .top surface layers of cement.

As is suggested in my above mentioned copending application, in order to have the pavement or other construction harmonize with its naturalsurroundings, or for other purposes, special selected aggregates may be used either in the main body of the concrete, if its top surface is to be directly exposed,-or in the top layer such as at 12. That is, ag-

"' gregate material of distinctive colors,'textures and arrangements may be used and sufficiently exposed to give the desired appearance, but without removing so much of the cement as to endanger the firm and perma nent embedment of the aggregate in the concrete under the stress of. trafiic and under severe weather conditions.

Surfaces of this character have a, further advantage in that if a non-absorbent stone aggregate is used, the actual water absorptive area of the concrete maybe reduced to about 20% or less of the total top area. The absorp tion of an undesirable quantity of water, which under severe weather conditions promotes deterioration of the concrete, is therefore prevented and at the same time a durable stone surface of exceptional wearing qualities is presented to the traffic. The removal of the surface layers of cement contributes a further advantage inthat skin tensions arising from layers overrich in cement at the surface are eliminated with the consequent elimination of the tendency of such tensions to initiate cracking.

If desired, instead of laying the pavement in two courses as shown in Fig. 1,'it may be laid in one course with the usual type of base, and the top coating containing a larger percentage of stone may then be poured onth'e base before the base is hardened. The sur face of this construction may be treated in the same manner as the surfaces above de= scribed. V

Notwithstanding the foregoing advantages of the revealed aggregate surfaces, an asphalt top-coating over a concrete base is preferred under some circumstances. Such a construction is shown in Fig. 3, in which a concrete base 14 is provided substantially according to the constructions shown in either Fig. 1 or Fig. 2. A layer of asphalt as at 15 is then applied to this roughened treated surface. The projecting aggregate will permit the asphalt to be securely lockedto the concrete, with the result that the common waving of asphalt tops and flowing of the asphalt on grades during hot weather will be substantially "eliminated. Such constructions are particularly advantageous on lift and draw bridges. The elevated position of the bridge may be maintained even in hot weather without fear of dislodgment or fiow ing of the asphalt coating.

While the invention has been described in detail with respect to particular preferred examples thereof which give satisfactory results, it will be understood by those skilled in the art after understanding the invention, that various changesand modifications may be made without departing from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed as new and desired to be said base a layer of concrete containing ansecured by Letters Patent of the United 7 States is:

1. The method of forming a monolithic body of concrete for bearing trafiic, which comprises pouring a body of concrete and superimposing upon the same a layer of con create embodying a relatively higher percentage of stone aggregate, and treating the upper surface of said layer with a material for delaying the setting of the concrete which when removed will reveal the aggregate.

2. The method of forming a concrete traffic way, which comprises pouring a concrete base and chemically treating the top surface of the same before it becomes hardened to remove the surface layers of cement therefrom and to expose the aggregate, and thereafter applying to said base a surface layer of concrete containing a high percentage of stone and also chemically treating the top surface of said layer to reveal the aggregate.-

3. The method of forming a concrete traffic way, which comprises pouring a'concrete base and chemically treating the top surface of the same before it becomes hardened to remove the surface layers of cement therefrom and to expose the aggregate to provide a good bonding surface, and thereafter applying to said base a layer of concrete containing an abnormal proportion of selected stone aggregate. a

4:. The method of forming a concrete traffic way, which comprises pouring a concrete base and chemically treating the top surface of the same before it becomes hardened to remove the surface layers of cement therefrom and to expose the aggregate to provide a good bonding surface, and thereafter applying to abnormal proportionlof selected stone aggregate, and also chemically treating the top surface of said layer to expose substantially the entire top surface areas of the upper layer of stone. 5. The method of forming a body of concrete for bearing traffic, which comprises pouring a body of concrete and chemically treating theupper surface thereof to reveal the aggregate to form a good bonding surface comprising the rough projecting aggregate particles, and applying to said surface a layer of asphalt.

In testimony whereof I have signed my name to this specification.

NATHAN C. JOHNSON. 

